Polishing machine



MarchZl, 1939. w. H. WOOD rousnme momma Filed 001;. 21, 1938 FIB-EPatented Mar. 21, 1939 UNITED STATES PATENT OFFiE POLISHING MACHINEApplication October 21, 1938, Serial No. 236,309

'7 Claims.

The'invention relates to abrading machines, and more particularly to apolishing machine for polishing spaced cylindrical portions on a workpiece.

One object of the invention is to provide a thoroughly practicalpolishing machine for polishing spaced portions on a completelyassembled electric motor rotor shaft or the like. Another object of theinvention is to provide a polishing machine in which the work piece,such as an assembled armature shaft, is supported to rotate on aflexible abrasive element which serves simultaneously to support andpolish spaced cylindrical portions thereon.

Another object of the invention is to provide such a machine with anopen top electric motor stator which corresponds in size with theassembled armature and shaft to be polished and which serves to rotatethe rotor shaft by its own power. Other objects will be in part obviousor in part pointed out hereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts, as will beexemplified in the structure to be hereinafter described, and the scopeof the application of which will be indicated in the following claims.

In the accompanying drawing, in which is shown one of various possibleembodiments of the mechanical features of this invention,

Fig. l is a perspective View of the improved motor rotor shaft polishingmachine;

Fig. 2 is a fragmentary end elevation thereof on a reduced scale;

Fig. 3 shows a fragmentary end view, on an enlarged scale, of theimproved polishing machine employing bonded abrasive elements instead ofa flexible abrasive element;

Fig. 4 is a fragmentary sectional view taken approximately on the line4-4 of Fig. 3; and

Fig. 5 is a fragmentary front elevation of the yieldable device whichengages one end of the rotor shaft during the polishing operation toassist in the oscillatory movement of the rotor shaft during polishing.

One embodiment of the improved polishing machine for polishing spacedcylindrical portions on a work piece has been disclosed in the drawing,comprising a base Ill having a pair of upwardly extending brackets H andIf each of which is provided in its upper surface with a semi-circulargroove l3 which serve as supports for continuous strips of flexibleabrasive paper or cloth l4 and IE to support and abrade spacedcylindrical portions l6 and ll of an assembled electric motor rotorshaft l8 having a rotor l9 fixedly assembled thereon.

The strip of abrasive paper I4 is wound up on a reel 25 which isrotatably supported by means of an upwardly extendingbracket 26 which isfixed to the base ill. The abrasive cloth or paper I4 passes over theupper surface of the bracket l I so that when the rotor shaft I8 is setin place, the abrasive paper will conform to the semicircular groove I'3so as to support and polish the portion iii of the rotor shaft l8. Areel 21 which is rotatably supported by an upwardly extending bracket 28fixed to the base it serves to wind up the used portion of the flexibleabrasive cloth or paper and is arranged so that after each polishingoperation or as frequently as is desired, the abrasive paper maybeadvanced to present a fresh abrading surface for the polishingoperation. The reel 2! has one of its side plates formed with ratchetteeth 29 which are arranged to be engaged by a pawl 38 which is in turnsupported by a bracket 3i fixedly mounted on the upwardly extendingprojection 28. By turning the ratchet teeth Ed in a counterclockwisedirection (Fig. l), the abrasive paper It may be advanced as desired.

The endless strip of abrasive paper I5 is similarly wound up upon a reel35 which is fixedly supported in an upwardly extending bracket 36 on thebase Ill. The abrasive strip it passes around beneath the cylindricalportion ll of the rotor shaft l8 and conforms with the semi-circulargroove 13 in the projection H. A reel Bl serves to wind up the wornportion of the flexible abrasive strip 15. This reel is rotatablysupported by'a bracket 38 which is fixedly mounted on the base Ill. Oneof the side plates of the reel 31 is provided with ratchet teeth 39which are arranged to be engaged by a ratchet pawl Ml supported by abracket 4! fixedly mounted on the supporting bracket 38.

To attain the main object of the invention, an open top electric motorstator 50 is fixedly mounted on the base ll! of the machine and ispositioned and arranged so that when the rotor I9 is set in position fora polishing operation, a desired and predetermined air gap will beprovided between the periphery of the rotor l9 and the internal surfaceof the open top electric motor stator 58. Power is supplied from anysuitable source, such as power lines M. A line switch 52 serves to closethe circuit to pass a current through the'open top electric motor stator'50 so as to transmit a rotary motion through the rotor H) to rotate therotor shaft i8 which is supported in operative abrading contact with theflexible abrasive elements I4 and I5. Thus, the rotor shaft I8 ispolished or lapped while being powered by its own assembled rotor I9.

It is desirable to rovide a relative oscillating movement between therotor shaft I8 and the flexible abrasive elements I4 and I5. In thepreferred form a motor driven oscillating mechanism is provided forproducing an endwise oscillating movement of the rotor shaft I8 duringthe rotation thereof so as to prevent individual abrasive grains fromthe elements I4 and I5 from producing rings or scratches around theperiphery of the cylindrical portions I6 and I1 during the polishing orlapping operation. This mechanism comprises an electric motor 60 whichis provided with a worm 6| mounted on the end of its rotor shaft. Theworm 6I meshes with a worm gear 62 which is fixedly mounted on arotatable shaft 63. The shaft 63 is journalled in suitable bearings inthe brackets 64 and 65 which are fixedly supported on the base Ill. Theshaft 63 carries a cam 66 which bears against a pivotally mounted rockarm 61 which is pivotally supported by means of a shaft 68 supported onthe base I 0. The rock arm 61 is provided with a projecting boss 69which is arranged to engage the end of the rotor shaft I8.

In order to maintain the end of the rotor shaft I6 in engagement withthe boss 69 during the reciprocation of the rotor shaft I8, aspring-pressed follower plunger I0 is slidably mounted in a bracket IIwhich is fixed to the projecting member II and is arranged to engage theleft-hand end of the rotor shaft I8 (Figs. 1 and 5). A spring I2 withinan enlarged portion 13 of the bracket II surrounds a stud 14 which isformed integral with the follower member 10 and is interposed betweenthe follower member 10 and the end of the opening in the enlargedportion 13. The compression of the spring 12 is suflicient to exert apressure in a direction toward the right (Figs. 1 and 5) at all times tomaintain the righthand end of the rotor shaft I8 against the boss 69 ofthe shaft reciprocating mechanism. It will be readily apparent from theforegoing disclosure that when the motor 68 is started rotating, the cam66 will rock the arm 61 and transmit an oscillating movement to therotor shaft I8 during rotation thereof, thus producing a rotarypolishing movement of the cylindrical portions I6 and I! which aresupported on the flexible abrasive elements I4 and I5 and at the sametime causing a relative endwise movement between these portions and theabrasive elements to produce a fine polished surface on the completelyassembled electric motor rotor shaft.

If desired, bonded abrasive elements may be utilized in place offlexible abrasive strips I4 and I5. As illustrated in Figs. 3 and 4, apair of bonded abrasive elements and 9| may be mounted on each of thesupporting projecting brackets II and I2. This construction is identicalon each of said brackets, consequently only the construction of themembers supported on the bracket II is illustrated. The abrasive members90 and BI may be clamped in position on the outwardly extendingprojection II by means of set screws 92 and 93. The abrasive blocks 90and 9| are preferably provided with an adjusting device to compensatefor wear so that the axis of the portion I6 of the rotor shaft I8 may bemaintained in the same position as the blocks Wear away. In thepreferred construction, as illustrated, the bonded abrasive blocks 90and SI are backed by wedge blocks 94 and 95 which may be adjusted. Ascrew 96 is provided which passes through a yoked portion 91 on thewedge block 94 and is screw threaded into the upwardly extending bracketII. By manipulation of the screw 96, the wedge may be moved eithertoward the right or toward the left to either raise or lower theabrasive block 90 so as to position the work axis in the desiredposition for a polishing operation and also serves to compensate forwear on the abrasive blocks after the abrasive block has worn duringuse. Similarly, the wedge block 95 may be adjusted by means of a screw98 which engages a yoked portion 99 on the end of the wedge block 95 andis also screw threaded into the member II so that adjustment of thescrew 98 serves to cause an endwise adjustment of the wedge block 94.

Similar bonded abrasive sticks are provided on the upper surface of theprojecting bracket II to engage, support and polish the cylindricalportion I1 of the rotor shaft I8.

The operation of this improved electric motor rotor shaft polishingmachine will be readily apparent from the foregoing disclosure. Acompletely assembled electric motor rotor shaft is placed in position onthe machine with the cylindrical portions I6 and I! engaging theflexible abrasive strips I4 and I5, respectively, to support the shaftfor a rotary motion on the brackets II and I2. The opposite ends of therotor shaft I8 are engaged by the boss 69 and the springpressed follower10. The line switch 52 is then closed to start rotation of the rotor I9on the rotor shaft I8 to rotate the shaft I3 under its own power for apolishing operation. At the same time the motor 60 is set in motion totransmit a reciprocatory movement through the cam 66 and the rock arm 6!to oscillate the rotor shaft I8 in an axial or endwise direction duringrotation of the shaft while the spaced cylindrical portions I6 and I!are supported on the abrasive elements I4 and I5, respectively, as shownin Figs. 1 and 2, or on the bonded abrasive sticks, as illustrated inthe modification shown in Figs. 3 and 4.

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all matter hereinbefore set forth or shown in theaccompanying drawing is to be interpreted as illustrative and not in alimiting sense.

I claim:-

1. In a polishing machine, an abrasive element which serves to supportand polish a cylindrical portion on a work piece and means including anopen top electric motor stator which surrounds a portion of said workpiece to rotate the same.

2. In a polishing machine, a continuous flexible abrasive element, asupporting member having a work supporting surface thereon to supportsaid abrasive so as to form an abrasive support for a Work piece to bepolished, and means including an open top electric motor stator whichsurrounds a portion of said work piece to rotate the same.

3. In a polishing machine, a pair of spaced work supporting membershaving partial cylindrical Work supporting surfaces thereon, acontinuous flexible abrasive element on each of said surfaces which arearranged to support a work piece for a polishing operation, a rotor onsaid work piece, and an open top electric motor stator partiallysurrounding said rotor and which serves 5 to rotate said rotor and shaftfor a polishing operation.

4. In a polishing machine, a pair of spaced WWWOIK supporting memberseach having a partial M" cylindrical work supporting grooved surface 10thereon, a continuous flexible abrasive element passing over each ofsaid surfaces and serving to support and polish a Work piece supportedthereon, a motorrotor on said work piece, an open top electric motorstator partially sur- 5 rounding said rotor and serving through saidrotor to rotate a shaft for a polishing operation, and means toreciprocate said work piece axially during rotation thereof.

5. In a polishing machine, a pair of spaced work 20 supporting memberseach having a partial cylindrical work supporting grooved surfacethereon, a continuous flexible abrasive element passing over each ofsaid surfaces and serving to support and polish a work piece supportedthereon, a 35 motor rotor on said Work piece, an open top electric motorstator partially surrounding said rotor and serving through said rotorto rotate a shaft for a polishing operation, and means including anelectric motor and a cam rotated thereby to reciprocate the work pieceaxially during rotation thereof.

6. In a polishing machine, a pair of spaced work supporting members eachhaving a partial cylindrical work supporting grooved surface thereon, acontinuous flexible abrasive element passing over said grooved surfacesand serving to support and polish spaced cylindrical portions on a Workpiece supported thereon, an open top electric motor stator partiallysurrounding an enlarged portion of said work piece, and means to supplyelectric power to said stator to rotate said work piece.

7. In a polishing machine, a pair of spaced work supporting members eachhaving a partial cylindrical work supporting grooved surface thereon, acontinuous flexible abrasive element passing over said grooved surfacesand serving to support and polish spaced cylindrical portions on a workpiece supported thereon, an open top electric motor stator partiallysurrounding an enlarged portion of said work piece, means to supplyelectric power to said stator to rotate said work piece for a polishingoperation, and means including a motor and cam to reciprocate the workpiece axially during rotation thereof.

WALLACE H. WOOD.

